Trailer coupling and automatic brake mechanism



Feb. 28, 1939. R. sl-aAr-FER 2,149,189 TRAILER COUPLING AND AUTOMATICvBRAKE'MECHANISM Filed Feb. 5, 1937 2 Sheets-Sheet l Feb. 28, 1939. E.R. SHAFFER 2,149,189

TRAILER COUPLING AND AUTOMATIC BRAKE MECHANISM Filed Feb. 5, 1957 2Sheets--Shee'fl 2 www l varying loads.

Patented Feb. 28, 1939 UNITED STATES PATENT OFFICE TRAILER COUPLING ANDAUTOMATIC BRAKE LIECHANISM Elgie n. shader, columbus, om ApplicationFebruary 5, 1937, Serial No. 124,291

9(7laiins.

'I'he present invention relates' to vehicle trains and especially tothose of the type consisting of an automobile and trailer, and consistsof certain improvements on the construction disclosed in my copendlngapplication Serial No. 104,276, led October 6, 1936.

One of the objects of the invention resides in the incorporation of acylinder and piston in the draft appliance, the construction being suchthat the uid may pass from one end of the cylinder to the other but at aregulated rate in accordance with certain adjustments, thereby providinga shock-absorber adaptable to varying loads.

A further object of the invention consists in the provision of aconnection between the draft appliance and the brake mechanism of thetrailer whereby over-running of the latter will cause an automaticapplication of the brakes.

Another object of the invention consists in providing mechanism forhandoperation of the trailer brakes even in the absence of fluid inthecylinder, such mechanism being adjustable for Another object of theinvention consists in the provision of means, set in operation eitherautomatically or by hand, to render the brake mechanism inoperative whenthe vehicle is backing.

A further object of the invention resides in the provision of a lock onthe coupling to prevent unauthorized detachment of the trailer from theleading. vehicle.

Another object of the invention resides in the provision of a simplifiedsignalling apparatus to automatically indicate at the rear of thetrailer either right or left turns of the leading vehicle.

-Other objects and advantages of the invention will 'be apparent fromthe following description when taken in connection with the accompanyingdrawings, in which,

Figure 1 is a plan view of the apparatus, parts being broken awayandparts being shown in section.

Figure 2 is a side elevational view, parts being broken away, and partsbeing indicated in dotted outline.

Figure 3 is an enlarged detail view, partly in section, of the means forrendering the brake inoperative. v

'Figure 4 is an enlarged detail view of a valve Y in the system.

Figure 5 is a horizontal sectional view taken on 0 line 5 5 of Figure 4;and

diagram.y

Referring to the drawings in more detail the Figure 6 is a detail viewindicating the wiring (ci. 18s- 112) numeral I indicates a portion of aleading vehicle, such as an automobile, and the numeral 2 indicates arearwardly extending bar to which is attached a ball 3 forming oneelement of a coupling for the trailer (not shown).

The numeral 4 indicates a socket member which is adapted lto releasablyengage 4over the ball 3, and the numeral 5 indicates a plunger mountedon the socket member and adapted to hold the parts in operativerelation. A spring 6 forces the plunger against ball 3 and a lock 1 isprovided for holding the plunger in this position until released by theproper key. A rod 8 is provided for manually disengaging the plungerfrom the ball after the lock is operated. f

The parts just described are mounted on the forward end of a draft bar9, and on the rear end of .this bar is a piston IIJiwhich is slidablymounted in a cylinder I'I. Associated with the cylinder II is a tank I2mounted on the upper 2g pair of longitudinal grooves or channels I5 toprovide for passage of fluid back and forth from one end of the cylinderto the other, and these channels are provided with screws or valves I6by means of which the rate of ilow through the channels may be regulatedas will appear hereinafter.

The forward end of the piston I0 is adapted to engage an annularshoulder Il in the ordinary operation of the device. The rear end of theplston is provided with a'tubular extension I8 slidably mounted in abearing I9 provided with a packing gland 20. In this tubular member isthreaded a rod 2l adapted to operate a brake operating piston 22 in acylinder 23 which is con-v nected to the main cylinder II. Cylinder 23is provided with a supply tank 24 for oil or other fluid 25, andpassages 26 and 21 permit communication between the cylinder and tank.This piston 22 is normally biased to the left by means of a spring 28which maintains the trailer brakesin released position. Movement of therod 2| tothe right imparts a similar movement to piston 22 and thus setsthe brake-operating mechanism in operation. By adjustment of the rod 2lit will be apparent that greater movement of piston III may be requiredbefore the brake mechanism is 'set in operation thereby adapting theapparatus to varying load requirements.

Formed on the inner wall of the cylinder I I is a J In order to applythe trailer brakes by hand an abutment 29 is provided on draft bar 9 andto this abutment is attached a rod 30 provided with an adjustment 3l. Ahand lever 32 is pivoted to the side of cylinder il as indicated bynumeral 33 and is pivotally connected at its lower end to rod 30. Byoperating lever 32 the piston iii may be moved to the right (Figure 1)thereby causing operation of piston 22 and thus an application of thebrakes on the trailer. The hand operation of the brakes together withthe adjustment 3i also provides a ready means for adjusting the brakesto varying loads.

It is essential to avoid automatic application of the brakes when thevehicle is backing, and for this purpose a spring-pressed valve M isprovided at the rear end of tank 2li. This valve opens into the rear endof cylinder 23 and functions to allow the escape of the brake-operatingfluid 2d into tank 2d when the valve 3d is open. The valve may be openedautomatically or by hand, and to this end an electromagnet 3F isprovided. This electromagnet includes an armature 36 having an extension3l adapted to open the valve when the electric circuit 3d is closed. Thecircuit includes a switch 39 for cooperation with the gear-shift leverllil, and a manuallyoperated switch (il which may be mounted on the dashor at any other convenient point. When the gear-shift lever is movedinto reverse the switch Bil is closed and the valve 3d is automaticallyopened, thereby allowing fiuid to escape into the tank 2li and thusavoid applying the brakes to the trailer. The brakes will also berendered inoperative of course if the manually-operated switch di isclosed, regardless of the position of the gear-shift lever.

For the purpose of giving automatic right and left-turn signals at therear of the trailer a bracket d2 is mounted on the bar 2 of the leadingvehicle i and this bracket is provided with a block of insulationmaterial i3 in which are mounted two contacts M. The forward exteriorsurface of the socket member il carries a brush l5 which will engageeither the one or the other of the contacts il when the leading vehiclemoves to either the right or the left and it will be understood thatthese contacts form parts of circuits including lamps at the rear of thetrailer to indicate right or left-turns. The operation of the lockingmechanism for the coupling is believed to be obvious without furtherdescription. As to the brake operation and shock-absorbing features ofthe apparatushowever certain details should be emphasized. As thetrailer overruns the leading vehicle, as when descending a hill therewill be a relative movement between the cylinder ii and piston ill thuscausing the piston to have an apparent movement to the right (Figure l).This movement of the piston causes the rod 2i to engage piston 22 andthus initiate the application of the brakes to the trailer. Furthermovement of the piston lil closes the port I4 thereby partly shuttingoff the tank i2.- Any additional movement of piston i0 to the iight ispermitted only las the fluid trapped in the right-hand end of thecylinder escapes through the small port M to tank i2 and through thechannels i5 and past the adjustable screws I6. It will be obvioustherefore that the brakes will be applied more or less gradually inaccordance with the adjustment of screws I6, and that such adjustmentsare to be made in accordance with the load on the trailer.

It is also to be noted that the channels I5 provide for the return ofuid from the front to the rear end of the cylinder thus providing anencellent shock-absorber between the two vehicles.

If, for any reason, it is desired to avoid application of the brakes onthe trailer, the valve 3d is opened by manually closing the switch illor .by placing the gear-shift lever in reverse. thereby rendering thebrake-operating fluid inoperative as heretofore described. V

From the foregoing description and the accompanying drawings it will beapparent to those skilled in the art that I have devised a. draftappliance including a hydraulic shock-absorber between the two vehicles;that automatic means are provided for applying the brakes on thetrailer; that such means is independent of fluid pressure in theshock-absorbing structure; that simple adjustments are provided forvarying the operation of the brakes as well as the shockabsorber inaccordance with the load on the trailer; that hand operation of thebrakes is provided; that the brake-operating mechanism is easilyrendered inoperative when desired; that automatic direction signals forma part of the mechanism; and that the coupling is so designed andconstructed as to prevent surreptitious detachment of the trailer.

In accordance with the patent statutes I have described what I nowbelieve to be the preferred embodiment of the invention, but inasmuch asvarious minor changes may be made in the details of construction withoutdeparting from the spirit of the invention it is intended that all suchchanges be included within the scope of the a pended claims.

What I claim is:

1. A combined coupling and brake-operating mechanism for a vehicletrain, including a cylinder` and piston in the coupling, a uidbrakeoperating cylinder and piston, means for imparting movement fromthe rst piston tothe second piston, and means for permitting'the escapeof uid from the second cylinder under certain conditions when operatedby the firstmentioned piston.

2. A. combined coupling and brake-operating mechanism for a vehicletrain, including a cylinder and piston in the coupling, a fluidbrakeoperating cylinder and piston, means on the first piston forengaging and operating the second piston, and an electrically-operatedvalve for permitting the escape of duid from the second cylinder whenthe circuit is closed.

3. A combined coupling and brake-operating mechanism for a vehicletrain, including a gear- Shift lever, a cylinder and piston in thecoupling, a uid brake-operating cylinder and piston, means on the iirstpiston for engaging and operating the second pistonfanelectrically-operated valve for permitting the escape of uid from thesecond cylinder, and a switch in the circuit, said switch being sopositioned as to be closed when the gear-shift lever is moved toreverse".

4. A combined' coupling and brake-operating mechanism for a vehicletrain, including a shockabsorbing cylinder and a brake-operatingcylinder rigidly connected end-to-end, a piston for cach of thecylinders, a draw bar connected to the piston of the shock-absorbingcylinder, means for permitting a circulation of uid around said piston,brake-operating means associated with the piston of the brake-operatingcylinder, and a lost-motion connection between the two pistons.

5. A combined coupling and brake-operating mechanism for a vehicletrain, includinga shockabsorbing cylinder and a brake-operating cylinderrigidly connected end-to-end, a piston for each of the cylinders, a drawlhar connected to the piston of the shock-absorbing cylinder,

` means for permitting a circulation of uid about each of the cylinders,a draw bar connected to the piston of the shock-absorbing cylinder,means for permitting a circulation of uid about said piston,brake-operating means associated with the brake-operating cylinder, anda rod adjustably connected to the shockabsorbing piston for engaging andoperating the brake-operating piston.

7. A combined coupling and brake-operating mechanism for a vehicletrain, including a shockalsorbing cylinder and brake-operating cylinderrigidly connected end-to-end, means for provid- .ing a shock-absorbingaction in the rst-menand` tioned cylinder and brake-operating action inthe other cylinder when the vehicles are caused to approach each other,and means for automatically releasing the brake-operating action in thebrake cylinder and providing shock-absorbing action in thefirst-mentioned cylinder when the vehicles move relatively apart.

8.-A combined coupling and brake-operating mechanism for a vehicletrain, including a cylinder and piston in the coupling, a. iiuidbrakeoperating cylinder and piston, means on the iirst piston forengaging and operating the second piston in one direction, a spring for,operating the second piston in the opposite direction, and means forrendering movement of the second piston in- .eiiective to apply thebrakes when operated by vthe ilrst piston.

9. A combined coupling and brake-operating mechanism for a vehicletrain, including a cylinder and piston inthe coupling, a uidbrakeoperating cylinder and piston, means for imparting movement fromthe first piston to the second piston, and means for rendering movementof the second piston ineffective to apply the brakes when operated bythe rst piston.

ELGIE R. SHAFFER.

